1. Field of the Invention
The present invention relates to improvements in a machine for meat treatment and maceration, with automatic loading and unloading, such as the machine described in prior U.S.A. Pat. No. 4,791,705 of same inventor, intended for allowing the tight closing door-lid of the meat treatment rotatable drum's loading and unloading hood inlet, to become independent from its support and means for positioning and separating the door with respect to the drum, with possibility of freely rotating from the moment the closing door-lid remains fitted and interlocked in the hood inlet.
2. Description of the Prior Art
The machine of the U.S.A. Pat. No. 4,791,705 includes a drum rotatable on its symmetry axis, with a loading hood inlet, opening, against which a closing door acts, the access opening in the drum being coaxial with the rotational axis, and defined in one of the ends of the internal chamber of the drum, driving and rolling elements monitoring and supporting the drum for rotation on a tiltable frame, articulated at one of its ends to a fixed support structure. The door of the meat treatment drum is assembled on a support structure independent of the drum, but connected with the tiltable frame, and has means for positioning and separating it with respect to the drum loading and unloading hood inlet, and means allowing its rotation on its center with respect to the support structure.
The door is arranged for fitting and locking in tight closing in the drum hood inlet in any position of rotation.
The need of the door-lid's locking means at the hood inlet of the drum is due to the particular treatment of the meat in this machine, which includes a series of subsequent vacuum, and pressure cycles, realized inside the drum, while it is rotating and the meat is subjected to a particular massage and/or beating so that pressure inside the drum of a significant magnitude may be sustained without the risk of opening or loss of pressure in the chamber.
The locking means of the door-lid, at the drum hood inlet, include a stem from which, at the central part of the door-lid, a series of radial blades extend, that are connected to a system of articulated levers, whose expansion by the stem axially operated in advance by the action of a linear hydraulic cylinder determines the displacement of some finger-like locking appendages, conveniently guided, whose ends are fitted in a locking position, in an annular recess defined in the drum's hood inlet inner wall.
According to the construction features shown in the U.S.A. Pat. No. 4,791,705, the door-lid that tightly closes the drum, remains all the time coupled to the support and handling structure of the door, and is formed by a support having a pivotable articulated arm to which the stem of an hydraulic cylinder is associated, to enable advance and return of the door-lid, toward and from the closing position, i.e., relative to the loading and unloading hood inlet of the drum. The rotatable arm has at its end a tubular housing that receives the referred to hydraulic cylinder which operates the locking means of the door-lid of the drum, and whose liner is also rotatable with respect to the housing, with the assistance of some proper bearings, in order to allow a free rotation of the door, with respect to the fixed support of the pivotable arm, in the closed position, when the drum is closed.
In the construction of said patent both the support bearing positioning means of the door-lid and the drum are supported on the same frame (the tiltable frame as described), producing the disadvantage of establishing a stiff positional coupling between the door-lid support structure and the drum, in the closing position of the and during meat treatment. Thus, should the loading hood inlet of the drum sustain a slight deviation from its ideal position (foreseeable for instance, by wearing out of the rolling means that support the drum on the frame), when rotating the drum, an excessive strain of the support structure would occur that would tend to deform it, shortening the assembly working life.